This is a basic and clinical study to elucidate the mechanisms of action of hematoporophyrin derivative plus light in the treatment and diagnosis of cancer. Three basic cell areas of investigation are proposed; 1. Further clarifying the cellular sites of binding; 2. Identifying the sites of phototoxicity (just because HpD binds to a particular site does not mean that that is the site of phototoxicity); 3. Identifying which HpD subcomponents are phototoxic and which are fluorescent (some may be both). In vitro studies will employ malignant and non-malignant cell lines with particular emphasis on toxicity and sites of binding structural alterations. Techniques used will be fluorescence detection, electron microscopy, and tissue culture. Animal studies will involve the use of different tumor systems with the main objectives being pathological and fluorescence analysis of HpD and light effects. Diagnostic studies will be done on human patients employing fluorescence detection in vivo plus serial biopsies followed by fluorescence analysis. Human treatment will involve treating patients with head and neck, gynecological, and bladder cancer.